Tuesday, 14 June 2005

This[story](http://theage.com.au/news/Science/Global-warming-cyclical-says-climate-expert/2005/06/12/1118514924793.html)on Bob Carter in the Age is a good one for playing[Global Warming SkepticBingo](http://deltoidblog.blogspot.com/2005/04/gwsbingo.php). Though I think Ishould add a rule to the effect that if a numerical claim is wrong bymore than an order of magnitude you get a free square on the bingoboard. Look at what Carter claims:

>Carbon dioxide was a minor greenhouse gas, responsible for 3.6 per>cent of the total greenhouse effect, [Carter] said. Of this, only 0.12 per>cent, or 0.036 degrees Celsius, could be attributed to human activity.

Actually, [calculationsshow](http://www.realclimate.org/index.php?p=142) that withoutCO2 the Greenhouse effect would be about 91% as strong.Further, he implies that only 0.12/3.6=3% of the CO2 in theatmosphere is due to human activity. But the concentration ofCO2 in the atmosphere has increased [from 280 ppm to 380ppm](http://www.grida.no/climate/ipcc_tar/wg1/fig3-2.htm) and thisincrease is [all due to humanactivity](http://www.realclimate.org/index.php?p=160). So, correctingCarter's numbers we have that 100/380=25% of the CO2 in theatmosphere is anthropogenic, so 25% of 9%=2.4% of the greenhouseeffect or 0.7 degrees Celsius is man-made. Carter is wrong by afactor of 20. Actually he's wrong by more than a factor of 20 sincehis calculation assumes that the quantity of water vapour in theatmosphere is fixed and this isn't true. As the globe warms there ismore water vapour in the atmosphere and this further strengthens thegreenhouse effect.

So how did something this inaccurate get into the Age?Well, Carter gave a speech to the Victorian Farmers Federation so thereporter who wrote the story was their agricultural reporter ratherthan their science reporter who might have noticed that Carter wasspouting a load of rubbish.